On a $50,000 account, the 1% rule means no single trade can cost you more than $500. Not the position value, not the stock price: the loss if the stop is reached. Everything else about the trade, including how many shares you buy, follows from that one number.
What the 1% rule is
Your maximum loss on any one trade is 1% of the account. Set the stop where the trade idea fails, work out the distance from your entry, and divide your 1% figure by that distance to get the share count.
The rule says nothing about how much you invest. A $50,000 account risking $500 might hold $10,000 of a stock with a $5 stop distance, or $3,500 of one with a $7 stop distance. The dollar at risk is fixed; the position value moves.
The arithmetic behind the 1% rule
Why a large loss is worse than it looks
Recovering from a drawdown takes a bigger percentage than the drawdown itself. The gain is calculated on the reduced balance. For a loss of L, the gain needed is L divided by (1 minus L).
| Account loss | Gain needed to recover |
|---|---|
| 10% | 11.1% |
| 20% | 25.0% |
| 30% | 42.9% |
| 40% | 66.7% |
| 50% | 100.0% |
At 10% the gap is small. At 50% you have to double what is left.
What a losing streak costs
Both tables below assume you recalculate the risk on each trade as a percentage of the balance you have at that point, which is what the rule says. Losing 1% eight times is not losing 8%.
At 1% risk per trade:
| Consecutive losses | Capital remaining | Account impact |
|---|---|---|
| 5 | 95.1% | minus 4.9% |
| 10 | 90.4% | minus 9.6% |
| 15 | 86.0% | minus 14.0% |
| 20 | 81.8% | minus 18.2% |
At 5% risk per trade:
| Consecutive losses | Capital remaining | Account impact |
|---|---|---|
| 5 | 77.4% | minus 22.6% |
| 10 | 59.9% | minus 40.1% |
| 15 | 46.3% | minus 53.7% |
| 20 | 35.8% | minus 64.2% |
Compare the first row of the second table with the last row of the first. Five losses at 5% leaves 77.4% of the account. Twenty losses at 1% leaves 81.8%. Four times as many losses, and it still costs less.
How to apply the 1% rule
The example below is hypothetical.
Step 1, the risk amount. $50,000 times 0.01 is $500.
Step 2, the stop distance. An entry at $100 with a stop at $95 gives $5 per share.
Step 3, the share count. $500 divided by $5 is 100 shares.
Step 4, the position value. 100 shares at $100 is $10,000, which is 20% of the account. Check this figure every time: a stop tight enough produces a position large enough to matter on an overnight gap, and a gap fills below your stop.
The 1% rule at two stop distances
Take a $50,000 account, $500 of risk, and an entry at $50 in both cases.
With the stop at $48, the distance is $2 and the position is $500 divided by $2, or 250 shares. At $50 a share that is $12,500, which is 25% of the account.
With the stop at $43, the distance is $7 and the position is 71 shares after rounding down. That is $3,550, or 7.1% of the account.
Same $500 at risk, one position three and a half times the size of the other. The stop distance did all the work.
Adjusting the 1% rule up or down
The 1% figure is a convention, not a law. What it buys you is visible in the streak tables above, and the same arithmetic prices any other choice.
A smaller number, such as 0.5%, halves the cost of every mistake and halves the result of every correct call. It fits a period when you are learning a new market, working through a losing run, or trading something whose behaviour you cannot yet predict.
A larger number costs more per error. Ten losses at 2% leave 81.7% of the account; ten at 5% leave 59.9%. The question to answer before raising the figure is whether you would still follow your rules with that much gone.
The 1% rule and total portfolio risk
One trade at 1% is not the constraint that binds. Five open positions at 1% each puts 5% of the account at risk if every stop is reached in the same week, and stops do get reached together.
Correlation makes it worse. Three stocks in the same sector are one bet wearing three names: in a sector-wide fall, all three stops go on the same day. Add correlated positions together as a single number when you check your total, not as three independent ones.
Decide the total you accept across all open trades and stop opening new ones when the sum reaches it. That number, not the per-trade number, is what determines your worst week.
The objection that 1% is too small
The rule caps the loss, not the gain. At a 2:1 target, a win on 1% of risk returns 2% of the account while a loss costs 1%. Win 45% of the time at that ratio and the average trade returns 0.45 times 2, minus 0.55 times 1, or plus 0.35R. On 1% risk that is 0.35% of the account per trade.
Turning a per-trade figure into an annual one needs your trade count, your brokerage costs and whether you compound, and none of those are knowable in advance. Your own closed trades supply them after the fact, which is the only place the number can honestly come from.
The rule also scales down without changing. A $10,000 account risks $100 per trade, and every calculation in this article works the same way on it.
What the 1% rule changes in practice
A defined maximum loss removes one decision from the moment you are least able to make it. When the stop is reached and the loss is a number you chose before entering, closing the position is administration rather than a judgement call under pressure.
It also makes your trades comparable. Every loss costs about the same, so a run of results describes the strategy rather than describing how much you happened to bet each time. That is what makes a win rate or an average R-multiple mean anything.
Applying the 1% rule consistently
Before entry, have three numbers written down: the entry price, the stop price, and the share count that follows from them. If the share count came from anywhere other than the first two, the rule is not running.
Round the share count down rather than up. A calculation that returns 143.8 shares becomes 143, not 144, because rounding up moves the loss above the limit you set.
Then check the order before you send it. The share count, the stop order reaching the broker, and the resulting dollar risk are three separate things. A stop you meant to place is not a stop.
The 1% rule quick reference
Each row uses a stop 5% below a $100 entry, which is $5 of risk per share.
| Account size | 1% risk | Share count | Position value |
|---|---|---|---|
| $10,000 | $100 | 20 | $2,000 |
| $25,000 | $250 | 50 | $5,000 |
| $50,000 | $500 | 100 | $10,000 |
| $100,000 | $1,000 | 200 | $20,000 |
| $250,000 | $2,500 | 500 | $50,000 |
Every position value in the last column is 20% of the account, because the stop percentage is the same in every row. Change the stop to 10% and every position halves.
Tracking the 1% rule in Swingfolio
The position size calculator runs steps 1 to 4 from your entry, stop, account value and risk percentage. It returns the share count, the dollar risk and the position value.
Inside the app, the trade form shows the trade's risk as a percentage of your portfolio value while you type it, turns that figure amber above 3%, and shows a warning line above 5%. Those thresholds are fixed rather than set by you, so treat them as a backstop against a slipped decimal, not as your 1% limit.
The dashboard gauge covers the total. Portfolio heat is the sum of entry minus stop, times the units still open, across every position, divided by portfolio value: what percentage of the account goes if every stop is reached at once. Swingfolio labels it as under control below 6%, elevated from 6% to 10%, and excessive above that.
Work out your 1% figure once, then check it against the heat gauge each time you open a position. Start the 30-day trial.